easy experiments with independent and dependent variables

9 Great Ways to Teach Variables in Science Experiments

by Katrina | Feb 17, 2024 | Pedagogy , Science | 1 comment

Science is a journey of exploration and discovery, and at the heart of every scientific experiment lies the concept of variables. Variables in science experiments are the building blocks of experimentation, allowing scientists to manipulate and measure different elements to draw meaningful conclusions.

Teaching students about variables is crucial for developing their scientific inquiry skills and fostering a deeper understanding of the scientific method.

In this blog post, we’ll explore the importance of teaching variables in science experiments, delve into the distinctions between independent, dependent, and controlled variables, and provide creative ideas on how to effectively teach these variable types.

So grab a coffee, find a comfy seat, and relax while we explore fun ways to teach variables in science experiments! 

The Importance of Teaching Variables in Science Experiments:

Foundation of Scientific Inquiry: Variables form the bedrock of the scientific method. Teaching students about variables helps them grasp the fundamental principles of scientific inquiry, enabling them to formulate hypotheses, design experiments, and draw valid conclusions.

Critical Thinking Skills: Understanding variables cultivates critical thinking skills in students. It encourages them to analyze the relationships between different factors, question assumptions, and think systematically when designing and conducting experiments.

Real-world Application: Variables are not confined to the laboratory; they exist in everyday life. Teaching students about variables equips them with the skills to critically assess and interpret the multitude of factors influencing phenomena in the real world, fostering a scientific mindset beyond the classroom.

In addition to the above, understanding scientific variables is crucial for designing an experiment and collecting valid results because variables are the building blocks of the scientific method.

A well-designed experiment involves the careful manipulation and measurement of variables to test hypotheses and draw meaningful conclusions about the relationships between different factors. Here are several reasons why a clear understanding of scientific variables is essential for the experimental process:

1. Precision and Accuracy: By identifying and defining variables, researchers can design experiments with precision and accuracy. This clarity helps ensure that the measurements and observations made during the experiment are relevant to the research question, reducing the likelihood of errors or misinterpretations.

2. Hypothesis Testing: Variables in science experiments are central to hypothesis formulation and testing. A hypothesis typically involves predicting the relationship between an independent variable (the one manipulated) and a dependent variable (the one measured). Understanding these variables is essential for constructing a hypothesis that can be tested through experimentation.

3. Controlled Experiments: Variables, especially controlled variables, enable researchers to conduct controlled experiments. By keeping certain factors constant (controlled variables) while manipulating others (independent variable), scientists can isolate the impact of the independent variable on the dependent variable. This control is essential for drawing valid conclusions about cause-and-effect relationships.

4. Reproducibility: Clear identification and understanding of variables enhance the reproducibility of experiments. When other researchers attempt to replicate an experiment, a detailed understanding of the variables involved ensures that they can accurately reproduce the conditions and obtain similar results.

5. Data Interpretation: Knowing the variables in science experiments allows for a more accurate interpretation of the collected data. Researchers can attribute changes in the dependent variable to the manipulation of the independent variable and rule out alternative explanations. This is crucial for drawing reliable conclusions from the experimental results.

6. Elimination of Confounding Factors: Without a proper understanding of variables, experiments are susceptible to confounding factors—unintended variables that may influence the results. Through careful consideration of all relevant variables, researchers can minimize the impact of confounding factors and increase the internal validity of their experiments.

7. Optimization of Experimental Design: Understanding variables in science experiments helps researchers optimize the design of their experiments. They can choose the most relevant and influential variables to manipulate and measure, ensuring that the experiment is focused on addressing the specific research question.

8. Applicability to Real-world Situations: A thorough understanding of variables enhances the applicability of experimental results to real-world situations. It allows researchers to draw connections between laboratory findings and broader phenomena, contributing to the advancement of scientific knowledge and its practical applications.

The Different Types of Variables in Science Experiments:

There are 3 main types of variables in science experiments; independent, dependent, and controlled variables.

1. Independent Variable:

The independent variable is the factor that is deliberately manipulated or changed in an experiment. The independent variable affects the dependent variable (the one being measured).

Example : In a plant growth experiment, the amount of sunlight the plants receive can be the independent variable. Researchers might expose one group of plants to more sunlight than another group.

2. Dependent Variable:

The dependent variable is the outcome or response that is measured in an experiment. It depends on the changes made to the independent variable.

Example : In the same plant growth experiment, the height of the plants would be the dependent variable. This is what researchers would measure to determine the effect of sunlight on plant growth.

3. Controlled Variable:

Controlled variables, also called constant variables, are the factors in an experiment that are kept constant to ensure that any observed changes in the dependent variable are a result of the manipulation of the independent variable. These are not to be confused with control groups.

In a scientific experiment in chemistry, a control group is a crucial element that serves as a baseline for comparison. The control group is designed to remain unchanged or unaffected by the independent variable, which is the variable being manipulated in the experiment.

The purpose of including a control group is to provide a reference point against which the experimental results can be compared, helping scientists determine whether the observed effects are a result of the independent variable or other external factors.

Example : In the plant growth experiment, factors like soil type, amount of water, type of plant and temperature would be control variables. Keeping these constant ensures that any differences in plant height can be attributed to changes in sunlight.

Science variables in science experiments

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Best resources for reviewing variables in science experiments:

If you’re short on time and would rather buy your resources, then I’ve compiled a list of my favorite resources for teaching and reviewing variables in science experiments below. While there is nothing better than actually doing science experiments, this isn’t feasible every lesson and these resources are great for consolidation of learning:

1. FREE Science Variables Posters : These are perfect as a visual aide in your classroom while also providing lab decorations! Print in A4 or A3 size to make an impact.

2. Variable scenarios worksheet printable : Get your students thinking about variable with these train your pet dragon themed scenarios. Students identify the independent variable, dependent variable and controlled variables in each scenario.

3. Variable Valentines scenarios worksheet printable : Get your students thinking about variables with these cupid Valentine’s Day scenarios. Students identify the independent variable, dependent variable and controlled variables in each scenario.

4. Variable Halloween scenarios worksheet printable : Spook your students with these Halloween themed scenarios. Students identify the independent variable, dependent variable and controlled variables in each scenario.

5. Scientific Method Digital Escape Room : Review all parts of the scientific method with this fun (zero prep) digital escape room! 

6. Scientific Method Stations Printable or Sub Lesson : The worst part of being a teacher? Having to still work when you are sick! This science sub lesson plan includes a fully editable lesson plan designed for a substitute teacher to take, including differentiated student worksheets and full teacher answers. This lesson involves learning about all parts of the scientific method, including variables.

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9 teaching strategies for variables in science experiments.

To help engage students in learning about the different types of scientific variables, it is important to include a range of activities and teaching strategies. Here are some suggestions:

1. Hands-on Experiments: Conducting hands-on experiments is one of the most effective ways to teach students about variables. Provide students with the opportunity to design and conduct their experiments, manipulating and measuring variables to observe outcomes.

Easy science experiments you could include might relate to student heart rate (e.g. before and after exercise), type of ball vs height it bounces, amount of sunlight on the growth of a plant, the strength of an electromagnet (copper wire around a nail) vs the number of coils.

Change things up by sometimes having students identify the independent variable, dependent variable and controlled variables before the experiment, or sometimes afterwards.

Consolidate by graphing results and reinforcing that the independent variable goes alone the x-axis while the dependent variable goes on the y-axis.

2. Teacher Demonstrations:

Use demonstrations to illustrate the concepts of independent, dependent, and controlled variables. For instance, use a simple chemical reaction where the amount of reactant (independent variable) influences the amount of product formed (dependent variable), with temperature and pressure controlled.

3. Case Studies:

Introduce case studies that highlight real-world applications of variables in science experiments. Discuss famous experiments or breakthroughs in science where variables played a crucial role. This approach helps students connect theoretical knowledge to practical situations.

4. Imaginary Situations:

Spark student curiosity and test their understanding of the concept of variables in science experiments by providing imaginary situations or contexts for students to apply their knowledge. Some of my favorites to use are this train your pet dragon and Halloween themed variables in science worksheets.

5. Variable Sorting Activities:

Engage students with sorting activities where they categorize different variables in science experiments into independent, dependent, and controlled variables. This hands-on approach encourages active learning and reinforces their understanding of variable types.

6. Visual Aids:

Utilize visual aids such as charts, graphs, and diagrams to visually represent the relationships between variables. Visualizations can make abstract concepts more tangible and aid in the comprehension of complex ideas.

7. Technology Integration:

Leverage technology to enhance variable teaching. Virtual simulations and interactive apps can provide a dynamic platform for students to manipulate variables in a controlled environment, fostering a deeper understanding of the cause-and-effect relationships.

Websites such as   Phet   are a great tool to use to model these types of scientific experiments and to identify and manipulate the different variables

8. Group Discussions:

Encourage group discussions where students can share their insights and experiences related to variables in science experiments. This collaborative approach promotes peer learning and allows students to learn from each other’s perspectives.

9. Digital Escape Rooms:

Reinforce learning by using a fun interactive activity like this scientific method digital escape room.

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Teaching variables in science experiments is an essential component of science education, laying the groundwork for critical thinking, inquiry skills, and a lifelong appreciation for the scientific method.

By emphasizing the distinctions between independent, dependent, and controlled variables and employing creative teaching strategies, educators can inspire students to become curious, analytical, and scientifically literate individuals. 

What are your favorite ways to engage students in learning about the different types of variables in science experiments? Comment below!

Note: Always consult your school’s specific safety guidelines and policies, and seek guidance from experienced colleagues or administrators when in doubt about safety protocols. 

Teaching variables in science experiments

About the Author

Katrina Harte is a multi-award winning educator from Sydney, Australia who specialises in creating resources that support teachers and engage students.

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15 Independent and Dependent Variable Examples

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An independent variable (IV) is what is manipulated in a scientific experiment to determine its effect on the dependent variable (DV).

By varying the level of the independent variable and observing associated changes in the dependent variable, a researcher can conclude whether the independent variable affects the dependent variable or not.

This can provide very valuable information when studying just about any subject.

Because the researcher controls the level of the independent variable, it can be determined if the independent variable has a causal effect on the dependent variable.

The term causation is vitally important. Scientists want to know what causes changes in the dependent variable. The only way to do that is to manipulate the independent variable and observe any changes in the dependent variable.

Definition of Independent and Dependent Variables

The independent variable and dependent variable are used in a very specific type of scientific study called the experiment .

Although there are many variations of the experiment, generally speaking, it involves either the presence or absence of the independent variable and the observation of what happens to the dependent variable.

The research participants are randomly assigned to either receive the independent variable (called the treatment condition), or not receive the independent variable (called the control condition).

Other variations of an experiment might include having multiple levels of the independent variable.

If the independent variable affects the dependent variable, then it should be possible to observe changes in the dependent variable based on the presence or absence of the independent variable.  

Of course, there are a lot of issues to consider when conducting an experiment, but these are the basic principles.

These concepts should not be confused with predictor and outcome variables .

Examples of Independent and Dependent Variables

1. gatorade and improved athletic performance.

A sports medicine researcher has been hired by Gatorade to test the effects of its sports drink on athletic performance. The company wants to claim that when an athlete drinks Gatorade, their performance will improve.

If they can back up that claim with hard scientific data, that would be great for sales.

So, the researcher goes to a nearby university and randomly selects both male and female athletes from several sports: track and field, volleyball, basketball, and football. Each athlete will run on a treadmill for one hour while their heart rate is tracked.

All of the athletes are given the exact same amount of liquid to consume 30-minutes before and during their run. Half are given Gatorade, and the other half are given water, but no one knows what they are given because both liquids have been colored.

In this example, the independent variable is Gatorade, and the dependent variable is heart rate.  

2. Chemotherapy and Cancer

A hospital is investigating the effectiveness of a new type of chemotherapy on cancer. The researchers identified 120 patients with relatively similar types of cancerous tumors in both size and stage of progression.

The patients are randomly assigned to one of three groups: one group receives no chemotherapy, one group receives a low dose of chemotherapy, and one group receives a high dose of chemotherapy.

Each group receives chemotherapy treatment three times a week for two months, except for the no-treatment group. At the end of two months, the doctors measure the size of each patient’s tumor.

In this study, despite the ethical issues (remember this is just a hypothetical example), the independent variable is chemotherapy, and the dependent variable is tumor size.

3. Interior Design Color and Eating Rate

A well-known fast-food corporation wants to know if the color of the interior of their restaurants will affect how fast people eat. Of course, they would prefer that consumers enter and exit quickly to increase sales volume and profit.

So, they rent space in a large shopping mall and create three different simulated restaurant interiors of different colors. One room is painted mostly white with red trim and seats; one room is painted mostly white with blue trim and seats; and one room is painted mostly white with off-white trim and seats.

Next, they randomly select shoppers on Saturdays and Sundays to eat for free in one of the three rooms. Each shopper is given a box of the same food and drink items and sent to one of the rooms. The researchers record how much time elapses from the moment they enter the room to the moment they leave.

The independent variable is the color of the room, and the dependent variable is the amount of time spent in the room eating.

4. Hair Color and Attraction

A large multinational cosmetics company wants to know if the color of a woman’s hair affects the level of perceived attractiveness in males. So, they use Photoshop to manipulate the same image of a female by altering the color of her hair: blonde, brunette, red, and brown.

Next, they randomly select university males to enter their testing facilities. Each participant sits in front of a computer screen and responds to questions on a survey. At the end of the survey, the screen shows one of the photos of the female.

At the same time, software on the computer that utilizes the computer’s camera is measuring each male’s pupil dilation. The researchers believe that larger dilation indicates greater perceived attractiveness.

The independent variable is hair color, and the dependent variable is pupil dilation.

5. Mozart and Math

After many claims that listening to Mozart will make you smarter, a group of education specialists decides to put it to the test. So, first, they go to a nearby school in a middle-class neighborhood.

During the first three months of the academic year, they randomly select some 5th-grade classrooms to listen to Mozart during their lessons and exams. Other 5 th grade classrooms will not listen to any music during their lessons and exams.

The researchers then compare the scores of the exams between the two groups of classrooms.

Although there are a lot of obvious limitations to this hypothetical, it is the first step.

The independent variable is Mozart, and the dependent variable is exam scores.

6. Essential Oils and Sleep

A company that specializes in essential oils wants to examine the effects of lavender on sleep quality. They hire a sleep research lab to conduct the study. The researchers at the lab have their usual test volunteers sleep in individual rooms every night for one week.

The conditions of each room are all exactly the same, except that half of the rooms have lavender released into the rooms and half do not. While the study participants are sleeping, their heart rates and amount of time spent in deep sleep are recorded with high-tech equipment.

At the end of the study, the researchers compare the total amount of time spent in deep sleep of the lavender-room participants with the no lavender-room participants.

The independent variable in this sleep study is lavender, and the dependent variable is the total amount of time spent in deep sleep.

7. Teaching Style and Learning

A group of teachers is interested in which teaching method will work best for developing critical thinking skills.

So, they train a group of teachers in three different teaching styles : teacher-centered, where the teacher tells the students all about critical thinking; student-centered, where the students practice critical thinking and receive teacher feedback; and AI-assisted teaching, where the teacher uses a special software program to teach critical thinking.

At the end of three months, all the students take the same test that assesses critical thinking skills. The teachers then compare the scores of each of the three groups of students.

The independent variable is the teaching method, and the dependent variable is performance on the critical thinking test.

8. Concrete Mix and Bridge Strength

A chemicals company has developed three different versions of their concrete mix. Each version contains a different blend of specially developed chemicals. The company wants to know which version is the strongest.

So, they create three bridge molds that are identical in every way. They fill each mold with one of the different concrete mixtures. Next, they test the strength of each bridge by placing progressively more weight on its center until the bridge collapses.

In this study, the independent variable is the concrete mixture, and the dependent variable is the amount of weight at collapse.

9. Recipe and Consumer Preferences

People in the pizza business know that the crust is key. Many companies, large and small, will keep their recipe a top secret. Before rolling out a new type of crust, the company decides to conduct some research on consumer preferences.

The company has prepared three versions of their crust that vary in crunchiness, they are: a little crunchy, very crunchy, and super crunchy. They already have a pool of consumers that fit their customer profile and they often use them for testing.

Each participant sits in a booth and takes a bite of one version of the crust. They then indicate how much they liked it by pressing one of 5 buttons: didn’t like at all, liked, somewhat liked, liked very much, loved it.

The independent variable is the level of crust crunchiness, and the dependent variable is how much it was liked.

10. Protein Supplements and Muscle Mass

A large food company is considering entering the health and nutrition sector. Their R&D food scientists have developed a protein supplement that is designed to help build muscle mass for people that work out regularly.

The company approaches several gyms near its headquarters. They enlist the cooperation of over 120 gym rats that work out 5 days a week. Their muscle mass is measured, and only those with a lower level are selected for the study, leaving a total of 80 study participants.

They randomly assign half of the participants to take the recommended dosage of their supplement every day for three months after each workout. The other half takes the same amount of something that looks the same but actually does nothing to the body.

At the end of three months, the muscle mass of all participants is measured.

The independent variable is the supplement, and the dependent variable is muscle mass.  

11. Air Bags and Skull Fractures

In the early days of airbags , automobile companies conducted a great deal of testing. At first, many people in the industry didn’t think airbags would be effective at all. Fortunately, there was a way to test this theory objectively.

In a representative example: Several crash cars were outfitted with an airbag, and an equal number were not. All crash cars were of the same make, year, and model. Then the crash experts rammed each car into a crash wall at the same speed. Sensors on the crash dummy skulls allowed for a scientific analysis of how much damage a human skull would incur.

The amount of skull damage of dummies in cars with airbags was then compared with those without airbags.

The independent variable was the airbag and the dependent variable was the amount of skull damage.

12. Vitamins and Health

Some people take vitamins every day. A group of health scientists decides to conduct a study to determine if taking vitamins improves health.

They randomly select 1,000 people that are relatively similar in terms of their physical health. The key word here is “similar.”

Because the scientists have an unlimited budget (and because this is a hypothetical example, all of the participants have the same meals delivered to their homes (breakfast, lunch, and dinner), every day for one year.

In addition, the scientists randomly assign half of the participants to take a set of vitamins, supplied by the researchers every day for 1 year. The other half do not take the vitamins.

At the end of one year, the health of all participants is assessed, using blood pressure and cholesterol level as the key measurements.

In this highly unrealistic study, the independent variable is vitamins, and the dependent variable is health, as measured by blood pressure and cholesterol levels.

13. Meditation and Stress

Does practicing meditation reduce stress? If you have ever wondered if this is true or not, then you are in luck because there is a way to know one way or the other.

All we have to do is find 90 people that are similar in age, stress levels, diet and exercise, and as many other factors as we can think of.

Next, we randomly assign each person to either practice meditation every day, three days a week, or not at all. After three months, we measure the stress levels of each person and compare the groups.

How should we measure stress? Well, there are a lot of ways. We could measure blood pressure, or the amount of the stress hormone cortisol in their blood, or by using a paper and pencil measure such as a questionnaire that asks them how much stress they feel.

In this study, the independent variable is meditation and the dependent variable is the amount of stress (however it is measured).

14. Video Games and Aggression

When video games started to become increasingly graphic, it was a huge concern in many countries in the world. Educators, social scientists, and parents were shocked at how graphic games were becoming.

Since then, there have been hundreds of studies conducted by psychologists and other researchers. A lot of those studies used an experimental design that involved males of various ages randomly assigned to play a graphic or non-graphic video game.

Afterward, their level of aggression was measured via a wide range of methods, including direct observations of their behavior, their actions when given the opportunity to be aggressive, or a variety of other measures.

So many studies have used so many different ways of measuring aggression.

In these experimental studies, the independent variable was graphic video games, and the dependent variable was observed level of aggression.

15. Vehicle Exhaust and Cognitive Performance

Car pollution is a concern for a lot of reasons. In addition to being bad for the environment, car exhaust may cause damage to the brain and impair cognitive performance.

One way to examine this possibility would be to conduct an animal study. The research would look something like this: laboratory rats would be raised in three different rooms that varied in the degree of car exhaust circulating in the room: no exhaust, little exhaust, or a lot of exhaust.

After a certain period of time, perhaps several months, the effects on cognitive performance could be measured.

One common way of assessing cognitive performance in laboratory rats is by measuring the amount of time it takes to run a maze successfully. It would also be possible to examine the physical effects of car exhaust on the brain by conducting an autopsy.

In this animal study, the independent variable would be car exhaust and the dependent variable would be amount of time to run a maze.

Read Next: Extraneous Variables Examples

The experiment is an incredibly valuable way to answer scientific questions regarding the cause and effect of certain variables. By manipulating the level of an independent variable and observing corresponding changes in a dependent variable, scientists can gain an understanding of many phenomena.

For example, scientists can learn if graphic video games make people more aggressive, if mediation reduces stress, if Gatorade improves athletic performance, and even if certain medical treatments can cure cancer.

The determination of causality is the key benefit of manipulating the independent variable and them observing changes in the dependent variable. Other research methodologies can reveal factors that are related to the dependent variable or associated with the dependent variable, but only when the independent variable is controlled by the researcher can causality be determined.

Ferguson, C. J. (2010). Blazing Angels or Resident Evil? Can graphic video games be a force for good? Review of General Psychology, 14 (2), 68-81. https://doi.org/10.1037/a0018941

Flannelly, L. T., Flannelly, K. J., & Jankowski, K. R. (2014). Independent, dependent, and other variables in healthcare and chaplaincy research. Journal of Health Care Chaplaincy , 20 (4), 161–170. https://doi.org/10.1080/08854726.2014.959374

Manocha, R., Black, D., Sarris, J., & Stough, C.(2011). A randomized, controlled trial of meditation for work stress, anxiety and depressed mood in full-time workers. Evidence-Based Complementary and Alternative Medicine , vol. 2011, Article ID 960583. https://doi.org/10.1155/2011/960583

Rumrill, P. D., Jr. (2004). Non-manipulation quantitative designs. Work (Reading, Mass.) , 22 (3), 255–260.

Taylor, J. M., & Rowe, B. J. (2012). The “Mozart Effect” and the mathematical connection, Journal of College Reading and Learning, 42 (2), 51-66.  https://doi.org/10.1080/10790195.2012.10850354

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Ideas for Controlled-Variable Science Projects

Understanding the definition and different types of variables is vital to properly conducting any science experiment. An independent variable is what you intentionally change in order to measure the effect of the dependent variable.To measure both of these, you must also have controlled variables: factors that remain consistent throughout every part of the experiment. Controlled variables ensure that the different elements of an experiment are similar enough that you know what is being changed or tested.

Direct vs. Indirect Sunlight

This experiment checks whether a particular kind of plant prefers direct or indirect sunlight. Get two specimens of the same small plant that can easily be checked on and moved. Put one in an area that receives lots of direct sunlight. Put the other in an area that gets only indirect sunlight. Water both plants the same measured amount and see which grows better. This experiment demonstrates how sunlight affects different kinds of plants, reinforcing the differing needs of different kinds of plant life. The controlled variables in this experiment are the type of plant used and the amount of water received. With different kinds of plants, or inconsistent watering, how well each plant grew might not be a factor of sunlight alone.

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Experiment with what rolls faster by covering one of two planks with a smooth lining like shelf paper and thge other with a rough lining like carpet or astroturf. Place the planks at an angle and roll a tennis or golf ball down each plank simultaneously. Observe which ball reaches the ground first. In most cases, the ball will move fastest on the smooth surface, demonstrating the effect of friction on an object's acceleration. In this experiment, the controlled variable is the angle of the board and the type of ball you roll.

Does Sugar Dissolve Better in Hot Water?

Fill two identical containers with two cups of water each -- one hot and one cold. Add a teaspoon of sugar to each and stir the mixture the same number of times in each container. Use a stopwatch to record how long it takes for a teaspoon of sugar to dissolve in each. In most cases, the sugar will dissolve in the warm water faster, demonstrating that warm mediums -- in which the molecules are moving faster -- dissolve a solid faster than cold mediums. The ratios of water to sugar and the amount of stirring are both controlled variables in this experiment.

Does Water or Vinegar Clean a Penny Better?

Take two dirty pennies and place them in identical shallow containers that can hold liquid. Petri dishes are perfect for this, but a shallow bowl or empty yogurt cup would also work. Cover the penny in one container with 1/8 cup of water, and the other with 1/8 cup of vinegar. After a week, remove the pennies and see which has been cleaned more. The result will usually be that the vinegar cleans the pennies better, demonstrating that a lower-pH solution is better at cleaning discoloration due to oxidation. The volume of liquid and the material of the penny are both controlled variables in this experiment. This experiment is especially good for teaching the concept of a controlled variable if you include a third variable -- how dirty the pennies are.

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Beverlee Brick began writing professionally in 2009, contributing to various websites. Prior to this, she wrote curriculum and business papers in four different languages. As a martial arts and group fitness instructor, she has taught exercise classes in North America, Europe and Asia. She holds master's degrees in French literature and education.

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Independent and Dependent Variables Examples

The independent and dependent variables are key to any scientific experiment, but how do you tell them apart? Here are the definitions of independent and dependent variables, examples of each type, and tips for telling them apart and graphing them.

Independent Variable

The independent variable is the factor the researcher changes or controls in an experiment. It is called independent because it does not depend on any other variable. The independent variable may be called the “controlled variable” because it is the one that is changed or controlled. This is different from the “ control variable ,” which is variable that is held constant so it won’t influence the outcome of the experiment.

Dependent Variable

The dependent variable is the factor that changes in response to the independent variable. It is the variable that you measure in an experiment. The dependent variable may be called the “responding variable.”

Examples of Independent and Dependent Variables

Here are several examples of independent and dependent variables in experiments:

• In a study to determine whether how long a student sleeps affects test scores, the independent variable is the length of time spent sleeping while the dependent variable is the test score.
• You want to know which brand of fertilizer is best for your plants. The brand of fertilizer is the independent variable. The health of the plants (height, amount and size of flowers and fruit, color) is the dependent variable.
• You want to compare brands of paper towels, to see which holds the most liquid. The independent variable is the brand of paper towel. The dependent variable is the volume of liquid absorbed by the paper towel.
• You suspect the amount of television a person watches is related to their age. Age is the independent variable. How many minutes or hours of television a person watches is the dependent variable.
• You think rising sea temperatures might affect the amount of algae in the water. The water temperature is the independent variable. The mass of algae is the dependent variable.
• In an experiment to determine how far people can see into the infrared part of the spectrum, the wavelength of light is the independent variable and whether the light is observed is the dependent variable.
• If you want to know whether caffeine affects your appetite, the presence/absence or amount of caffeine is the independent variable. Appetite is the dependent variable.
• You want to know which brand of microwave popcorn pops the best. The brand of popcorn is the independent variable. The number of popped kernels is the dependent variable. Of course, you could also measure the number of unpopped kernels instead.
• You want to determine whether a chemical is essential for rat nutrition, so you design an experiment. The presence/absence of the chemical is the independent variable. The health of the rat (whether it lives and reproduces) is the dependent variable. A follow-up experiment might determine how much of the chemical is needed. Here, the amount of chemical is the independent variable and the rat health is the dependent variable.

How to Tell the Independent and Dependent Variable Apart

If you’re having trouble identifying the independent and dependent variable, here are a few ways to tell them apart. First, remember the dependent variable depends on the independent variable. It helps to write out the variables as an if-then or cause-and-effect sentence that shows the independent variable causes an effect on the dependent variable. If you mix up the variables, the sentence won’t make sense. Example : The amount of eat (independent variable) affects how much you weigh (dependent variable).

This makes sense, but if you write the sentence the other way, you can tell it’s incorrect: Example : How much you weigh affects how much you eat. (Well, it could make sense, but you can see it’s an entirely different experiment.) If-then statements also work: Example : If you change the color of light (independent variable), then it affects plant growth (dependent variable). Switching the variables makes no sense: Example : If plant growth rate changes, then it affects the color of light. Sometimes you don’t control either variable, like when you gather data to see if there is a relationship between two factors. This can make identifying the variables a bit trickier, but establishing a logical cause and effect relationship helps: Example : If you increase age (independent variable), then average salary increases (dependent variable). If you switch them, the statement doesn’t make sense: Example : If you increase salary, then age increases.

How to Graph Independent and Dependent Variables

Plot or graph independent and dependent variables using the standard method. The independent variable is the x-axis, while the dependent variable is the y-axis. Remember the acronym DRY MIX to keep the variables straight: D = Dependent variable R = Responding variable/ Y = Graph on the y-axis or vertical axis M = Manipulated variable I = Independent variable X = Graph on the x-axis or horizontal axis

• Babbie, Earl R. (2009). The Practice of Social Research (12th ed.) Wadsworth Publishing. ISBN 0-495-59841-0.
• di Francia, G. Toraldo (1981). The Investigation of the Physical World . Cambridge University Press. ISBN 978-0-521-29925-1.
• Gauch, Hugh G. Jr. (2003). Scientific Method in Practice . Cambridge University Press. ISBN 978-0-521-01708-4.
• Popper, Karl R. (2003). Conjectures and Refutations: The Growth of Scientific Knowledge . Routledge. ISBN 0-415-28594-1.

Related Posts

Science Projects With Three Variables For Kids In Fifth Grade

The concept of variables in a science experiment can be confusing for fifth graders. Think of the independent variable as what you change in an experiment, the dependent variable as the response you observe because of what you changed, and the controlled variable as the things you keep the same so they don't interfere with your results. The independent variable must be something measurable that you can change in the experiment. The dependent variables must be able to be measured and caused by the independent variable. The controlled variable must not change during the experiment. Try some easy projects that use three variables to understand the importance of each variable in an experiment.

Do Seeds Germinate More Quickly in Fertilized Soil?

Plant seeds in identical seedling trays, using two trays of unfertilized soil and two seedling trays of fertilized soil, to see which soil helps the seeds germinate faster. Label the unfertilized seedling trays "A" and "B" and the fertilized seedling trays "C" and "D." The controlled variables are: same kind of seed, same type of soil, same amount of water from the same source applied at the same frequency, same amount of exposure to the sun, same room temperature and same dew point. The fertilizer added to trays C and D is the independent variable. The time for germination to take place and the height of the seedlings are dependent variables.

Does More Sugar Dissolve in Heated Water?

Compare how much sugar dissolves in containers of one cup of water, each at different temperatures. When sugar dissolves in water, you cannot see any sugar crystals floating in the water or settling on the bottom of the cup when you stop stirring; you'll use these visual indicators to compare how much has dissolved in each cup. You will change the temperature of the water, so this is the independent variable. The dependent variable is the amount of sugar that dissolves in each cup of water. The controlled variables are stirring each container the same amount and using sugar from the same bag.

Does Changing the Mass on the End of a Pendulum Affect the Period?

Tie a weight to the end of a 3 1/2-foot string, leaving a 5-inch tail of string so you can add additional weights later in the experiment. Hang the string from a dowel rod taped to the top of a cabinet. Mark the angle from which you will swing the pendulum, then release the weight. Time how long it takes to swing back and forth five times. One swing is called a period. Divide the time by five to get the average period for the first trial. Conduct two more trials and average the period for the three trials. Repeat the procedure with two weights and three weights. The varying weights are the independent variable, while the number of swings, or periods, is the dependent variable. The length of the string and the angle of the swing are controlled variables.

Does the Type of Surface Affect the Speed of a Toy Car?

Make a ramp with sides to make sure the car stays on the ramp. The ramp can be as simple as a board with modeling clay guard rails. You will test different surfaces, such as sand paper, floor tile or bare wood, on top of the ramp and measure the time and distance that a toy car travels using at least three trials each. The various surfaces on the ramp are the independent variables. The speed of the car, measured in distance traveled over a length of time, is the dependent variable. The controlled variables are using the same car, using the same ramp at the same angle, and letting go of the car without pushing at the same starting point.

• Science Buddies: Variables in Your Science Fair Project

Cite This Article

Strauch, Annette. "Science Projects With Three Variables For Kids In Fifth Grade" sciencing.com , https://www.sciencing.com/science-projects-three-variables-kids-fifth-grade-12089180/. 24 April 2017.

Strauch, Annette. (2017, April 24). Science Projects With Three Variables For Kids In Fifth Grade. sciencing.com . Retrieved from https://www.sciencing.com/science-projects-three-variables-kids-fifth-grade-12089180/

Strauch, Annette. Science Projects With Three Variables For Kids In Fifth Grade last modified August 30, 2022. https://www.sciencing.com/science-projects-three-variables-kids-fifth-grade-12089180/

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Independent & Dependent Variables Practice

I have found my students have a great deal of difficulty with the concept of independent and dependent variables. Newer textbooks call these variables “manipulated and responding” but that still doesn’t seem to make it easier.

We practice these scenarios in class and do multiple labs to learn the concepts. Often they are just simple labs that can be done in a short class period. Like this lab on heat storage .

I designed this worksheet as a way to get students to quickly identify the variables in an experiment. Each scenario is only a couple sentence long, such as ” One grape is placed in tap water and another grape is placed in salt water.”

In the chart, students would identify the independent variable as the type of water. Then, identify what responded. In this case, the mass of the grape after a day.

The worksheet design is simple. It’s a quick way to practice variables, but not other aspects of the scientific method. If you want a more robust worksheet on the scientific method, check out “ Early Discoveries in Science .” Students identify variables as well as draw conclusions from observations.

For differentiation, I also have a simpler version (low level) of the worksheet that gives multiple choice options. This version may also be useful for test preparation with other groups.

Grade Level: 8-10 Time Required: 15-20 minutes

Shannan Muskopf

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What Are Variables In Science

Variables in scientific investigations are essential! Find out what variables mean, what are three variables you need to know, plus examples of controlled, independent, and dependent variables in experiments. Enjoy hands-on and easy science experiments for kids today!

What Are Scientific Variables?

In science, variables are any factor that can be changed in an experiment to help us understand how different factors can affect an experiment or situation.

Specifically, three different variables help us answer the question we are investigating. Identifying these variables before you start will guide your decisions about how to conduct your experiment and how to measure the results.

💡 We use variables when we apply the scientific method to our experiments.

Three Types of Variables

The three kinds of variables are independent, dependent, and controlled variables. You want to implement variables in any scientific investigation to ensure a fair test.

💡 Let’s use our Plant Growth Experiment as an example to understand the variables better.

Independent Variable

In a science experiment, the independent variable is the factor you will change. This variable affects the dependent variable.

You can identify the independent variable by looking at what can exist in differing amounts or types and what is directly related to your experiment’s question.

👉 For example, if you are testing how different amounts of water affect plant growth, the amount of water would be the independent variable. You can change how much water you give the plants to see how it affects their growth.

💡 Remember, choose only one independent variable for your experiment!

Dependent Variable

The dependent variable is the factor that you observe or measure in an experiment. It is the variable that is affected by changes made to the independent variable. Note: the number of dependent variables can be more than one.

👉 The dependent variable would be the plant’s growth. We are measuring the plant’s growth to see how it is affected by the volume of water it is given.

Controlled Variables (Constant Variables)

Control variables are the factors that you keep the same in the science experiment. This helps ensure that any changes in the dependent variable are due to the independent variable and not something else.

With some experiments, you may choose to set up a control that has no amount of the independent variable added to it. All other factors are the same. This is great for comparison.

👉 For example, in our plant growth experiment you would keep the type and amount of soil, including the type of fertilizer, the type of plant, and the amount of sunlight, all the same, so that you can be sure that any changes in plant growth are only due to the different amounts of water you give them. You could also have one plant that you give no water.

Grab the FREE printable science project variables sheet!

Easy Scientific Investigations With Variables

Here are a few examples of independent and dependent variables in science experiments . All of these experiments are very easy to do and use simple supplies! Of course, you could change out the variables in these examples by asking a different question.

Apple Browning Experiment

Investigate what stops cut apples from turning brown. Does lemon juice work the best or does something else?

👉The independent variable is the type of substance you apply to the apples to stop or slow down browning. The dependent variable is the amount of browning on each apple slice.

Balloon Experiment

Kids love this easy science experiment. Blow up a balloon with a vinegar and baking soda chemical reaction. Find out what amount of baking soda makes for the biggest balloon.

👉The independent variable is the amount of baking soda added to the vinegar, and the dependent variable is the size of the balloon.

Celery and Food Coloring

Demonstrate how water travels through plants via capillary action with cut celery.

👉The independent variable could be the length of time the celery is immersed in the water. The dependent variable is how far the food coloring has traveled throughout the celery.

Color Taste Test

Does the color of food or drink affect how it tastes? Explore whether the color of a drink affects how it is perceived in terms of taste.

👉The independent variable would be the color of the drink and your dependent variable the perceived taste.

Floating Orange

A fun and easy experiment that explores the density of peeled and unpeeled oranges in water.

👉The independent variable could be the type of orange you use. The dependent variable is how much of the orange floats in water.

Grow Crystals

Turn your crystal growing activity into an experiment that explores how temperature of the solution affects the size of the crystals.

👉The independent variable is the temperature and the dependent variable is the size of the crystals.

Ice Melting Experiment

Explore what makes ice melt faster.

👉 The independent variable is the type of substance added to the ice. You could try salt, sand and sugar. The dependent variable is the time it takes to melt the ice.

Magic Milk Experiment

Kids will love this color changing milk experiment with food coloring and dish soap. Investigate what happens when you use different types of milk.

👉The independent variable is the type of milk and the dependent variable is how the food coloring moves through the milk.

Popsicle Stick Catapult

This is a fun physics activity especially for kids who love tinkering and building stuff, and you can turn it into a science experiment. Investigate how far an object travels as it weighs more.

👉 The independent variable is the type of object you use on your catapult (vary by weight). The dependent variable is the distance it travels. This is a good experiment for repeating several times so you can average the results.

Salt Water Density Experiment

Explore the density of salt water vs fresh water with this simple science experiment. What happens to an egg in salt water? Will the egg float or sink?

👉The independent variable is the amount of salt added to fresh water. The dependent variable is the distance of the egg from the bottom of the glass.

Seed Germination Experiment

Turn this seed germination jar into an easy science experiment by exploring what happens to seed growth when you change the amount of water used.

👉 The independent variable is the amount of the water used for each seed jar. The dependent variable is the length of the seedling over a period of time.

Variables and Writing A Hypothesis

Choosing variables is essential for writing a good hypothesis because variables help you define what you are testing and observing in a science experiment. A hypothesis predicts how one variable (the independent variable) affects another (the dependent variable). It explains the relationship between the independent and dependent variables.

💡 Learn more about how to write a good hypothesis for kids.

Helpful Science Resources

Here are a few resources that will help you introduce science more effectively to your kiddos or students and feel confident when presenting materials. You’ll find helpful free printables throughout.

Science Vocabulary: Introducing some fantastic science words to kids is never too early. Get them started with a printable science vocabulary word list .

What Is A Scientist? Learn about the different types of scientists and what they do. Read What Is A Scientist

Science Books: Sometimes, the best way to introduce science concepts is through a colorfully illustrated book with characters your kids can relate to! Check out this fantastic list of science books .

Science Practices: These eight science and engineering practices are less structured and allow for a more free – flowing approach to problem-solving and finding answers to questions.

Fun Science Experiments To Try: Don’t just read about science, go ahead and enjoy one of these fantastic kids science experiments !

Printable Science Projects For Kids

If you’re looking to grab all of our printable science projects in one convenient place plus exclusive worksheets and bonuses like a STEAM Project pack, our Science Project Pack is what you need! Over 300+ Pages!

• 90+ classic science activities  with journal pages, supply lists, set up and process, and science information.  NEW! Activity-specific observation pages!
• Best science practices posters  and our original science method process folders for extra alternatives!
• Be a Collector activities pack  introduces kids to the world of making collections through the eyes of a scientist. What will they collect first?
• Know the Words Science vocabulary pack  includes flashcards, crosswords, and word searches that illuminate keywords in the experiments!
• My science journal writing prompts  explore what it means to be a scientist!!
• Bonus STEAM Project Pack:  Art meets science with doable projects!
• Bonus Quick Grab Packs for Biology, Earth Science, Chemistry, and Physics

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